MEC DGICYT PB95-0685, 1996-1999

Principal Investigator: José Luis Micol.
Investigators: Pedro Robles Ramos, Héctor Candela Antón, María Rosa Ponce and Antonio Vera Tornel.
División de Genética. Universidad de Alicante (1996-1997). Universidad Miguel Hernández (1997-1999).

Molecular genetics of leaf morphogenesis in Arabidopsis thaliana

Although there is a vast inventory of mutations affecting plant morphology, only recently some research groups have tried to make extensive studies of developmental processes in plants by means of the analysis of wide groups of morphological mutants. There are numerous studies on leaf ontogeny in plants, for instance, but no one of them corresponds to an exhaustive search for mutations affecting genes involved in the control of the development of such an important organ.

With the purpose of contributing to the causal analysis of leaf development in plants, we are attempting to identify as many as possible of the genes involved in leaf ontogeny in the model system Arabidopsis thaliana. We are following in parallel several approaches: (a) a saturation mutagenesis, searching for mutations affecting leaf architecture (we have found 856 EMS induced and 520 fast neutron induced putative mutants), (b) the study of mutants with abnormal leaf morphology obtained from already existing collections (165 mutants from the AIS collection), and (c) the study of natural variability in leaf architecture in ecotypes (wild type strains) trying to identify monogenic traits related with leaf size, shape and vein pattern, with the purpose of mapping the corresponding genes.

We propose in this project (1) to finish the complementation and linkage analysis of most, if not all already mentioned natural variants and new and old mutations, in order to define allelism and map position of each one, (2) to obtain double and, if possible, triple mutant combinations, with the purposes of studying functional interactions among genes, establishing their individual and coordinate roles in leaf development and to ellaborate a genetic model for leaf growth, development and pattern formation, (3) to try to isolate T-DNA induced mutants with abnormal vein patterning, (4) to initiate the molecular analysis of one of the genes identified in our screenings for mutants with abnormal leaves, ultracurvata, whose mutations produce leaves with the limb curled along the midvein axis, and (5) to try the same with one of the genes with mutations perturbing the vein pattern, identified by insertional mutagenesis with T-DNA.